1. Field of the Invention
The present invention relates to a mobile terminal. More particularly, the present invention relates to a method and device for inputting characters in a mobile terminal.
2. Description of the Related Art
Due to developments in mobile telecommunications, mobile terminals have become popular, enabling users to communicate over the phone while moving. Through such mobile terminals, it is possible to transmit and receive data such as text as well as voice. Mobile terminals comprise a key input unit for inputting data such as characters necessary to transmit and receive data.
It is a current trend that mobile terminals are becoming smaller and lighter for their portability. As the size of terminals has become smaller, the area occupied by the key input unit has been reduced. As a result, most current terminals comprise only basic function keys and number keys. However, the number of required keys on a mobile terminal is increasing in order to meet the need to perform various functions. Therefore, mobile terminals have been developed so that a single key can perform different operations according to the time duration or number of key-pressings. It is easy to establish a key for performing one operation (for example, pressing the “1” key for a longer duration in order to select a function mode). However, the number of keys on the key input unit is not sufficient to designate each key to input a particular character according to the key-pressing time and number. To solve this problem, conventional terminals assign a plurality of characters to a single key so that the plurality of characters can be input according to the number of key-pressings.
FIG. 1 is a view illustrating a conventional 12-key keypad for inputting digits, characters or symbols in a mobile terminal.
Referring to FIG. 1, a user can input a Korean character  or an English character “S” by pressing the “7” key three times consecutively. Specifically, when the “7” key is pressed three times in the Korean input mode, three different characters  and  are input in turn in the order imprinted on that key. In the English input mode, “P,” “R” and “S” are input in turn with the three consecutive pressings of the “7” key. A direction key is generally used to input a space between characters. However, a change of mode to the English input mode should precede the pressing of the direction key to input a space between Korean characters. When the user wishes to input an emoticon or a character in a next line, he or she has to hit the direction key repeatedly until a cursor is placed on the next line.
As explained above, a conventional keypad of a mobile terminal assigns a plurality of characters to each number key. Accordingly, to input a desired character, the user has to press the corresponding key from one to two or more times according to the order in which the character is imprinted on the key.
With the repeated pressing of a key, characters imprinted on that key are displayed in turn on the display screen of the mobile terminal. Since the number of keys provided on the conventional keypad is limited to twelve, each key is generally assigned three or more characters. To input a desired character, the user has to press the corresponding key up to four or five times. It is cumbersome and time-consuming to repeatedly press a key. Also, it shortens the life of the key.
As a solution to the above problems, characters can be assigned to the number keys in a new layout that enables input of each character with fewer keystrokes. However, users may be inconvenienced until they get accustomed to the new layout of characters.